As somebody turning 26 soon and at university, I currently still have a PA. however I am currently unaware of when the support stops and what the transition period begins.
However I am not worried too much about it as I had failed a year of university and due to this I was not supported by my PA or LA for the year as they could not offer me help. I wouldn’t say I am used to not receiving support, however it gave me an experience to understand what is to come in the next few months as I finish university and with little support!